Cartridge for endless coil of tape

ABSTRACT

Cartridge for holding an endless coil of tape having innermost and outermost turns connected by a connecting loop. The cartridge has a bottom, a cover and a stationary support projecting upwardly from the bottom which is tilted at an angle to the vertical and larger at the top than at the bottom so that a coil thereon is urged into a frusto-conical configuration, with one side of the coil confined between the support and the bottom and a diametrically opposite part confined between the support and the cover.

Umted States Patent 1 1 3,854,669

Cailliot Dec. 17, 1974 CARTRIDGE FOR ENDLESS COIL F TAPE 3,244,471 4/1966 Mead 352/72 1971 M lk k 242 55.|9 A [75] Inventor: Serge Leon Louis Cailliot, 3590221 6/ a 0W5 Neuilly-sur-Seine, France [73] Assignee: Georges Tcherkassky, Parc Primary y Taylor i -M France Attorney, Agent, or Firm-Brisebois & Kruger [22] Filed: Feb. 8, 1973 2i A l. N 330588 1 pp 0 57 ABSTRACT Foreign Applicafion Priority Data Cartridge for holding an endless coil of tape having Feb. 11, 1972 France 72.04699 innermost and outermost turns connected by a con- Jan. 15, I973 France 73.01333 I necting loop. The cartridge has a bottom, a cover and a stationary support projecting upwardly from the bot- [52] U.S. Cl. 242/55J9 A, 242/55.2l tom which is tilted at an angle to the vertical and [51] Int. Cl Bh 17/48 larger at the top than at the bottom so that a coil [58] Field Of Search... 242/55.l9 A, 5 1; thereon is urged into a frusto-conical configuration, 352/128, 78, 72; 179/1002 Z with one side of the coil confined between the support and the bottom and a diametrically opposite part con- [56] References Cited fined between the support and the cover.

UNITED STATES PATENTS 2,922,642 H1960 Cousino 242/55.19 A 5 Claims, 5 Drawing Figures ab a" PATENTELBEC I 71974 a m e CARTRIDGE FOR ENDLESS COIL OF TAPE SUMMARY OF THE INVENTION This invention relates to cartridges containing tapes which are wound in an endless coil and in which the innermost turn of the coil is connected to the outermost turn by means of a connecting loop which passes over the remaining turns of the coil.

Difficulties have been encountered in manufacturing such cartridges, since it is desirable that they be capable of operating when in any physical position, that they be small and inexpensive, and that they be adapted to be driven by a driving spindle and pressure roller alone, to the exclusion of any such device as a rotating turntable or a radially positioned set of rollers capable of driving the different turns of the tape coil with said driving spindle simultaneously exerting a traction on the inner turn thereof to compensate for the difference in the respective rates of winding and unwinding by the inner and outer turns (which results from the difference in their diameters) by causing a radial displacement of the various turns, which is facilitated by the advance of the strips.

In my prior US. Pat. No. 3,787,057, I have suggested a solution to this problem consisting in the use of a strip having a certain stiffness capable of transmitting a spring effect from said innermost turn to said outermost turn or vice versa either through said connecting loop or through the assembly of contiguous turns making up said coil. The use of a stiff resilient strip also permits the advancement of the tape in either direction, that is to say, when traction is exerted either on the innermost turn or the outermost turn.

However, it should be noted that, despite the satisfactory operation of a cartridge holding a coil consisting of turns of a stiff tape which are only slightly spaced from each other, the price of this tape, which must be specially manufactured for this purpose, at least in the case of a magnetic sound tape, substantially increases that of a cartridge equipped with this coil. Moreover, when a small strip of endless magnetic tape is used, the need for operation in both directions exists only for certain particular applications, and the mere provision of a coil having its innermost and outermost turns connected by a connecting loop is sufficient to permit operation in a single direction to produce an uninterrupted playing of background music, for example, and to make rewinding unnecessary.

Applicant has now succeeded in devising a new cartridge capable of using a coil consisting of a flexible tape such as an ordinary magnetic tape, for example and which is capable of operating regardless of the orientation of the cartridge.

This result has been attained by mounting on the bottom of such a cartridge, equipped in a conventional manner with a cover having a top wall parallel to said bottom, a support of a particular shape consisting of a lower part which is relatively thin and has a substantially constant height, which part is perpendicular to the bottom and leads to a trapezoidal part having an axis of symmetry inclined with respect to a perpendicular to said bottom, and terminating in a triangular part having an edge parallel to the bottom and to the top wall of the cover so as to impart a slightly conical profile to the innermost turn of a coil consisting of a plurality of turns, with the conicity of its contiguous turns varying in a progressive manner from the innermost turn, which bears almost diametrally on the oblique sides of said trapezoid, to a substantially cylindrical outermost turn inclined with respect to the bottom and to the top wall of the cover, the part of this outermost turn furthest from the bottom being at the same level as the part of the connecting loop connecting it to the innermost turn near one of the oblique edges of said trapezoidal part, so that said connecting loop lies in a single plane over all its length and the tension exerted on the tape by the driving spindle is uniformly distributed over its entire width from its lower edge, which rests on the upper edge of the part of said support having a constant thickness at a height substantially equal to half that of the cartridge, to its upper edge, which substantially coincides with the upper edge of this support which, as has already been said, is parallel to the cartridge bottom.

Independently of the substantial savings which result from the use of a conventional sound tape, in the case of a cartridge for a sound tape, the new cartridge also has the by no means negligible advantage of making it possible to reduce the thickness of the tape constituting said coil and consequently obtaining, without an increase in the price and bulk, a greater number of turns corresponding to a greater length of tape and listening or projection time, which may be as much as double that of corresponding cartridges using a relatively stiff tape and having a substantial springiness.

It will be hereinafter seen that, this coil, each turn of which has a generally conical shape, but all of the turns of which are spaced from each other, cannot in practice move very much inside the cartridge because of the multiplicity ofthe surfaces, lines or points of contact between the coil and the casing of the cartridge.

In particular, the trapezoidal shape of the part of this support, which cooperates with the innermost turn, helps by its inclination to hold the coil gripped between the cartridge bottom and the top wall of the cover.

The position of this coil with respect to the cartridge is not absolutely unchangeable, but varies so little that the connecting loop remains constantly oriented parallel to the bottom of the cartridge and the top wall of the cover. It should be noted that, without resorting to a truly stiff resilient strip, having a real spring effect, it is possible, by utilizing a strip a little thicker than that of ordinary projection film, to cause the strip mounted in this cartridge to travel in either direction.

The new cartridge also comprises preferably, and particularly when the innermost turn has a substantial diameter, a second support similar to the first and parallel thereto. This second support is pivotally mounted to turn about an axis perpendicular to the cartridge bottom and subjected to the pressure of a spring tending to separate it from the first support so that the assembly of these two supports keeps the diameter of the innermost turn at its maximum value, thus making it possible to maintain a substantially constant play between the turns of the coil regardless of the limited variations in the length of the tape mounted in the cartridge or variations in thickness due to progressive use of these tapes, while assuring rapid absorption of any decrease in the tension on this strip at the level of the connecting loop.

However, in order to obtain this result, it is necessary to not only exert traction on the outermost turn of the coil but also to exert pressure on the innermost turn of the coil, which pressure must tend to rotate said coil by its innermost turn.

Such a rotary drive requires not only the use of a tape of increased stiffness but also the provision on the cover of the cartridge of an internal rib adapted to' serve as an abutment for the substantially straight part of the connecting loop between the reading table and two supports between which this connecting loop passes before reaching the innermost turn of the coil. This rib preferably has a height substantially equal to the width of the tape used, but in order to avoid any possibility of wear against this coil it is advantageous to progressively reduce its height as it approaches the coil.

In a conventional manner, the parts of this cartridge comprising its bottom and cover may be snapped together after mounting the endless tape inside the cartridge, and this greatly facilitates the manufacture of such cartridges.

The characteristics of the new cartridge according to the invention will be better understood from a reading of the following description of a preferred embodiment of the cartridge, which utilizes two supports. This embodiment which is given purely by way of illustration and example, and is described with reference to the accompanying drawings on which:

FIG. I is an exploded perspective view showing the parts constituting the cartridge and the horizontal path of the connecting loop of the tape;

FIG. 2 is a plan view of the part of this cartridge on which the supports are mounted, together with the coil, said part being shown without its cover;

FIG. 3 is a vertical sectional view taken through the cartridge along the line IIIIII of FIG. 2;

FIG. 4 is a top plan view ofa new cover provided with the internal rib required when the tape is to be driven in two directions; and

FIG. is a sectional view taken along the line VV of FIG. 4.

FIG. 1 shows that the two parts 1 and 2 snap together to form the cartridge. This figure also shows the supports 3 and 4 which are perpendicular to the bottom of the box 1, as well as the parts 3a and 4a of these supports which are of constant thickness.

The support 4 is mounted to pivot about an axis 6 perpendicular to the bottom 5 and a spring 6a tends to separate the two ends of the supports 3 and 4 which are of maximum height from each other. The components 1 and 2 snap together in a known manner forming no part of the present invention. The means used are similar to those provided in the aforesaid application Ser. No. 23,745, and will not be described again. The upper part 7 of the coil lies between an inner part 7a and an outer part 7b. This coil is generally conical in shape near its inner part 7a but its upper surface 7 and its lower surface 8 are respectively curved away from the level of their points of contact 8a and 7c with the bottom 5, on the one hand, and the top wall 2a, on the other hand, as may be seen in particular on FIG. 3. It will be seen from FIG. 3 that the upper surface 7 of the coil has a convex part 7d adjacent the cover 2 and the concave part 7e diametrically opposite to the convex 7c and adjacent the bottom. This shape of the coil is characteristic of the invention.

FIG. 3 shows the cartridge in a horizontal position. Under these conditions the coil is in contact at 8a with the bottom 5 along the full length ofa generatrix, while the lower surface 8 of the coil is supported by the two parts 3a and 4a of the supports 3 and 4 at 8!) and 8c.

On the other hand, there is a clearance 9 visible on FIG. 3 between the innermost turn of the coil and the lower part of the trapezoidal portions of the supports 3 and 4, whereas this clearance is non-existant at the top of the trapezoidal portions of these supports. When the cartridge is differently oriented, the surfaces of contact between the trapezoidal parts of the supports 3 and 4 and on the bottom 5 and the top wall 2a of the cover 2 are different.

In any case, this multiplicity of possible points, lines or surfaces of contact greatly restricts the possible deformation of the coil and, in combination with the inclination of the axis of the innermost turn of the coil with respect to the pivotal axis 6 of the support 4, makes it possible to obtain the result sought, to wit, the operation of the cartridge with a flexible tape which may be a magnetic sound tape of a standard type.

Moreover the possibility of using such a flexible tape having little stiffness makes it possible to substantially increase the listening time and the grip on the turns of the coil as compared to an embodiment using a stiff resilient tape, The trapezoidal form of the supports 3 and 4 also makes it possible to hold the connecting loop 10 in a plane parallel to the side of the cartridge regardless of the orientation of this cartridge.

It will be noted, however, that this connecting loop may twist a little at 10a, as shown for example on FIG. 2, in order to connect at with an external turn having a certain inclination with respect to the bottom 5 of the cartridge, as shown in particular on FIG 3. FIG. 2 also shows the driving spindle 11 which normally exerts a traction on the innermost turn of the coil in the direction of the arrow 12.

As has been seen above, by using a strip having a slightly greater stiffness without having a true spring effect, it is possible to advance the tape in the opposite direction by simultaneously exerting traction on the outermost turn and pushing on the innermost turn of the coil.

Finally FIGS. 4 and 5 show the internal rib 13 against which a substantially straight section of the connecting loop 10 rests when the tape is driven in a direction opposite to that of arrow 12 in FIG. 2 by exerting pressure on the tape in the corresponding direction.

The presence of this rib 13, on the wall 13a of which the substantially straight part of the tape rests, holds this part of the connecting loop in the substantially straight line required to achieve the desired result, while preventing it from forming undesirable arcs which would interfere with the transmission of the pressure exerted on the connecting loop via the innermost turn of the coil, which is rotated to drive said coil.

It will, of course, be understood that the embodiment which has just been described may be modified as to detail, and certain components thereof may be replaced by equivalent components, without thereby departing from the basic principles of the invention. In particular, the rib 13 may be replaced by a line of bosses which are not connected to each other but are nevertheless capable, in view of the stiffness of the strip used, of insuring satisfactory driving from the innermost turn of the coil.

What is claimed is:

1. Cartridge holding an endless coil of tape having an innermost turn encircling a central opening and an outermost turn, said turns being connected by a connecting loop extending over the remaining turns of said coil, said cartridge comprising a bottom part, a cover part, a stationary pillar means projecting upward from said bottom part, passing through the central opening in said coil, and holding said coil away from the peripheral wall of the cartridge, said pillar means having a portion of its upper peripheral surface which is inclined inwardly of said cartridge at a slight angle to a perpendicular to said bottom, said portion constituting an abutment surface about which said connecting loop is bent away from said innermost turn, supporting means on the same side of pillar means as said inclined surface, said supporting means defining a narrow surface generally parallel to said cover part which confines a first section of said coil at a first level between said narrow surface and said cover part, and guide means on the opposite side of said pillar means from said supporting means and defining a narrow surface spaced from the top of said cartridge which confines a second section of said tape at a second level between said surface on said guide means and said bottom part, with the upper surface of said second coil section lying slightly below the lower surface of said first coil section so that said connecting loop may pass substantially untwisted across said second coil section, said tape having a stiffness sufficient to provide for said coil to rotate in either direction within said cartridge when said connecting loop is friction driven in that direction.

2. Cartridge as claimed in claim 1 in which said guide means extends along one side of the path of travel of said connecting loop across said second section of said coil, and the abutment surface of said pillar contacts the surface of said tape facing away from said guide means.

3. Cartridge as claimed in claim 1 comprising means for receiving a driving spindle and pressure foot at a predetermined position and means for guiding said connecting loop to said position between said spindle and pressure foot.

4. Cartridge as claimed in claim 1 comprising second pillar means similar and substantially parallel to said first pillar means and also passing through said central opening, said second pillar means being mounted to swing about an axis perpendicularly mounted on said bottom, and resilient means biasing at least the portion of said second pillar means within said central opening away from the corresponding portion of said first pillar means.

5. Cartridge as claimed in claim 4 in which said connecting loop passes between said first and second pillar 

1. Cartridge holding an endless coil of tape having an innermost turn encircling a central opening and an outermost turn, said turns being connected by a connecting loop extending over the remaining turns of said coil, said cartridge comprising a bottom part, a cover part, a stationary pillar means projecting upward from said bottom part, passing through the central opening in said coil, and holding said coil away from the peripheral wall of the cartridge, said pillar means having a portion of its upper peripheral surface which is inclined inwardly of said cartridge at a slight angle to a perpendicular to said bottom, said portion constituting an abutment surface about which said connecting loop is bent away from said innermost turn, supporting means on the same side of pillar means as said inclined surface, said supporting means defining a narrow surface generally parallel to said cover part which confines a first section of said coil at a first level between said narrow surface and said cover part, and guide meanS on the opposite side of said pillar means from said supporting means and defining a narrow surface spaced from the top of said cartridge which confines a second section of said tape at a second level between said surface on said guide means and said bottom part, with the upper surface of said second coil section lying slightly below the lower surface of said first coil section so that said connecting loop may pass substantially untwisted across said second coil section, said tape having a stiffness sufficient to provide for said coil to rotate in either direction within said cartridge when said connecting loop is friction driven in that direction.
 2. Cartridge as claimed in claim 1 in which said guide means extends along one side of the path of travel of said connecting loop across said second section of said coil, and the abutment surface of said pillar contacts the surface of said tape facing away from said guide means.
 3. Cartridge as claimed in claim 1 comprising means for receiving a driving spindle and pressure foot at a predetermined position and means for guiding said connecting loop to said position between said spindle and pressure foot.
 4. Cartridge as claimed in claim 1 comprising second pillar means similar and substantially parallel to said first pillar means and also passing through said central opening, said second pillar means being mounted to swing about an axis perpendicularly mounted on said bottom, and resilient means biasing at least the portion of said second pillar means within said central opening away from the corresponding portion of said first pillar means.
 5. Cartridge as claimed in claim 4 in which said connecting loop passes between said first and second pillar means. 